Hemorrhagic Stroke by Warren T. Kim, M.D. Ph.D.

Hemorrhagic Stroke from acute rupture of a cerebral blood vessel is a devastating disease, and more common than generally appreciated.In the United States, the annual incidence of hemorrhagic stroke is approximately 30 per 100,000 people.

While representing only a small (15%) subset of all strokes, hemorrhagic stroke is particularly deadly and destructive. Thirty-day mortality is approximately 50%, and 50% of the survivors suffer significant permanent disability.

Although frequently related to hypertensive small vessel disease, many hemorrhagic strokes are due to rupture of a discrete cerebrovascular lesion. In the case of spontaneous subarachnoid hemorrhage, about 85% are from a ruptured intracranial aneurysm. Other vascular causes include arteriovenous malformation, arteriovenous fistula, dissection, and vasculopathy/vasculitis.

Essential initial treatment involves basic life support, control of blood pressure, treatment of seizures, management of bleeding/coagulopathy, control of intracranial pressure, and sometimes emergent ventriculostomy. Initial diagnostic work-up involves a detailed neurologic exam and non-invasive imaging, typically a head CT scan, which might show subarachnoid, intracerebral, and/or intraventricular hemorrhage that implicates an underlying cerebrovascular lesion such as an aneurysm or arteriovenous malformation. If the patient has a compelling story for the intracranial hemorrhage, but presents in a delayed fashion (when CT may not detect subacute blood), lumbar puncture and CSF analysis may be indicated.

When the clinical and radiologic findings confirm intracranial hemorrhage and suggest and underlying cerebrovascular lesion, the patient's survival and prognosis depend on receiving immediate high level care at a tertiary center with the facilities and expertise to manage these complex problems. California Pacific Medical Center is a Joint Commission Certified Stroke Center committed to providing the most advanced and comprehensive care for patients with stroke. Our Stroke Neurologists employ a telemedicine network to provide around-the-clock service to many Sutter-affiliated and other hospitals throughout Northern California.

In our neurological intensive care unit, close monitoring, blood pressure control, and cardiopulmonary support are provided for altered level of consciousness, neurocardiogenic injury and respiratory failure. Seizures, intracranial pressure, hydrocephalus, cerebral adema and mass effect are carefully managed, with ventriculostomy, craniectomy and open surgery provided by the Neurosurgery service. Using advanced non-invasive imaging technology, including a 64-slice CT scanner with CT angiography and perfusion mapping capability, as well as a 3-Tesla MRI with MR angiography and venography, we can often diagnose even small, 2-3 mm aneurysms and other hemorrhagic lesions.

If not, our dedicated neurointerventional suite is a state-of-the-art facility, with a biplane high-resolution digital angiography system with rotational capability for real-time 3-D processing and analysis, optimized to detect even the subtlest cerebrovascular pathology, and to provide the most detailed views for treatment planning.

Cerebral Aneurysms

An intracranial aneurysm is a focal out-pouching or ballooning of an arterial wall that develops due to chronic hemodynamic stress at a point of weakness, typically at a branch point (e.g. anterior communicating artery, middle cerebral artery bifurcation, carolid terminus, posterior communicating artery and basilar terminus.) Aneurysms are actually quite prevalent with a conservative estimate of 5 million people in the United States thought to have an aneurysm.

However, most are asymptomatic and may never cause a problem. Nonetheless, in a least 0.5% of cases, an aneurysm can slowly grow and weaken, much like a balloon as it stretches, and ultimately rupture.

When an acutely ruptured aneurysm is discovered, the next step is to clearly define its anatomy with a catheter angiogram, determining its size, shape, location and the precise relationship of the parent vessel, aneursym neck, any nearby branches. Given that a recently ruptured aneurysm had a high risk for catastrophic re-bleed, a decision can immediately be made about how best to treat the aneurysm, either endovascularly or by open surgery.

Minimally invasive endovascular treatment involves navigating a microcatheter through the blood vessels and into the aneurysm itself, then packing small, soft, thread-like platinum coils within the aneurysm sac until it clots and is secured. Where the anatomy is less favorable, a small balloon can be transiently inflated in the parent vessel to help position the coils in the aneurysm. Alternatively, a stent can be placed in the parent vessel, serving as a retaining lattice to pack coils in the aneurysm while leaving the parent vessel patent.

When an aneurysm is not readily amenable to endovascular treatment (e.g. very small, wide-based, branch originating off the sac), open microvascular neurosurgery is the definitive alternative treatment, where a craniotomy is performed and a surgical clip closed around the neck of the aneurysm, occluding its connection with the parent vessel. When an unruptured aneurysm is discovered incidentally, it can be thoroughly evaluated and observed over time, and electively treated if there are high-risk features, e.g. larger size (greater than 7mm), posterior circulation or posterior communicating artery, daughter lobule, symptomatic, enlarging, or history of prior ruptured aneurysm.

Arteriovenous Malformations

A cerebral arteriovenous Malformation (AVM) is a cluster or nidus of abnormally formed blood vessels with arteriovenous shunting of high-pressure arterial flow directly into veins, generally considered congenital/development in etiology. There are sometimes aneurysms in the nidus itself or in a feeding artery, which are related to the chronic high flow. Hemorrhage from an AVM can result from rupture of a recipient vein under the stress of high-pressure flow, or of a nidal or leading artery aneurysm. Unruptured AVMs often present with seizures, but also sometimes headache, progressive neurological deficit or incidentally.

Diagnosis and characterization of an AVM involves an MRI and MR angiography as wells as catheter angiography to determine the size, margins, and location of the nidus, feeding arteries, draining veins, and presence of nidal or feeding artery aneurisms. Ruptured AVMs have a high risk for catastrophic re-bleed, particularly during the first year after hemorrhage, while untreated unruptured AVMs have an annual risk of hemorrhage of approximately 2%. Therefore, management of cerebral AVMs involves considering the patient's age, comorbidities, and life expectancy, and weighing the prospective lifetime risk of hemorrhage versus the up-front risk of treatment.

Options include medical management (e.g. control of blood pressure and seizures), stereotactic radiosurgery to precisely target the nidus and slowly obliterate the AVM (best for small and unruptured AVMs, given the risk of radiation injury and 3-year latency to effect), open microsurgical resection (best for small, superficial AVMs) and endovascular embolization with n-BCA glue, Onyx, coils, or PVA particles to occlude the feeding arteries and penetrate the nidus (usually to decrease the AVM size or risk of hemorrhage prior to radiosurgery or open surgery, but occasionally curative alone.)

Vasospasm in the Aftermath of Subarachnoid Hemorrhage: "Adding Insult to Injury"

Subarachnoid hemorrhage-related vasospasm is a narrowing of the intracranial arteries due to irritation from surrounding blood breakdown products typically occurring during the first 14 days after hemorrhage, peaking between 7 to 10 days. Of sufficiently severe, this narrowing can become flow-limiting and cause ischemia and infarcts, resulting in severe disability and death in up to 10% of patients.

Optimal management in the ICU involves vasodilator therapy, close neurological monitoring and surveillance transcranial Doppler ultrasounds, CT angiography and perfusion analysis, and so-called "triple H" therapy (hypertension, hypervolemia, and hemodilution). When neurologic changes or non-invasive imaging suggests symptomatic or ominous worsening vasospasm despite the best medical management, catheter angiography is performed to accurately assess the degree of narrowing and flow limitation. If significant, selective intra-arterial infusion of vasodilator or balloon, angioplasty can be performed to aggressively treat the vasospasm.

6. Ogilvy CS, Stieg PE, Awad I, Brown RD Jr., Kondziolka D, Rosanwasser R. AHA Scientific Statement Recommendations for the management of intracranial arteriovenous malformations: a statement for healthcare professionals from a special writing group of the Stroke Council American Stroke Association.

Leaders in Hemorrhagic Stroke Treatment

We at the Calfornia Pacific Medical Center and Neuroscience Institute have an abiding commitment to offer the highest quality of care to patients suffering from cerebrovascular diseases such as hemorrhagic stroke. Working as an integral component of a strong multidisciplinary team that includes Stroke Neurology, Critical Care Medicine, Neuroradiology and Neurosurgery, our Neurointerventional service provides leading edge technology and unsurpassed expertise to diagnose and treat the most challenging cerebrovascular problems with the safest and most effective techniques.